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1. Field of the Invention
The apparatus of the present invention relates to angiographic catheters or guide catheters for coronary angioplasty or other coronary or vascular intervention.
2. General Background of the Invention
During percutaneous coronary intervention, guide catheters are advanced from the periphery, usually the femoral artery, into the aorta. The tip of the catheter is positioned in the ostium of a coronary artery. Subsequently, wires, balloon catheters, and other equipment are advanced through the guide catheter into the large epicardial coronary arteries to treat stenotic lesions.
A common problem during these procedures is the lack of guide support. As the operator attempts to advance the interventional equipment into the correct position within the coronary circulation, mechanical resistance is frequently encountered. This mechanical resistance may be due to a variety of factors, including but not confined to tortuosity of the target vessel, tight narrowing or calcification of stenoses, or lack of flexibility of the equipment used. This resistance may often have to be overcome by applying increased mechanical push of the equipment. Many guide catheters, however, lack sufficient stiffness to allow this somewhat forceful passing of the interventional equipment, and back out of their ostial position.
Operators will typically attempt to tackle this problem through changes of their interventional equipment such as wires or balloons, or through the exchange of their guide catheter for a stiffer or differently shaped model. Prolongation of the procedure with increased radiation exposure to the patient and operators, wasting of interventional equipment, and the abandoning of the type of intervention best suited for an individual lesion in favor of a suboptimal method requiring less guide support are all frequently seen consequences of lack of guide support. Moreover, the repeated, often forceful engagement of a coronary ostium with ill fitted equipment frequently leads to endothelial trauma and at times even to the dissection of the coronary artery.
The suggested new guide catheter features a plurality of wires, which are contained within the lumen of the catheter, extending from the proximal end of the catheter until its tip. Exit openings lead the wires outside the catheter lumen for a defined distance. Near the distal end of the catheter, the wires re-enter the catheter, and are securely anchored at or within the catheter wall.
A second segment of exposure of the wires to the exterior of the catheter is located at its proximal portion, the catheter segment which is not inserted into the patient""s vascular system, and which is manipulated by the operator. Small knobs on the outside of the catheter are connected to the wires at the proximal segment of the catheter. These small knobs connected to the wires allow the operator to advance and retract them, leading to their flexing away from (with advancing movements of the wires) or their repositioning adjacent to the body of the catheter (with retracting movements of the wires) at a defined section near its distal end. The bending out of the wire forms supporting loops, which firmly anchor the distal portion within the aortic root. The knobs located at the proximal portion of the wires allow for their being locked in any position. Adjustment of the degree of extension or retraction of the wires, and thus the size of the distal wire loops, allows for a safe and secure engagement of the distal opening of the catheter within the coronary ostium targeted.
There are numerous advantages of the present invention, as listed below.
1. There is ample guide support for the pushing of interventional equipment into the coronary circulation, since the guide catheter is backed by its wires against the opposite wall of the aortic root.
2. The touching of the wire bends against the aortic root can be used by the operator to better steer the distal opening of the guide catheter through rotational movements.
3. Undue engagement of the coronary ostium can be avoided, significantly lessening the risk of proximal ostial trauma of the coronary artery by the catheter tip with possible injury to the ostial endothelium.
4. During coronary angioplasty, the ensemble of the wire bends, in fact, allows to reliably disengage the catheter tip from the coronary ostium throughout most of the procedure, providing adequate blood supply into the coronary without the fear of loss of catheter position.
5. The risk of loss of coronary wire position, a not infrequent and potentially disastrous event during angioplasty, is substantially lessened due to the secured guide catheter position.
6. Less deep engagement and better coronary flow avoid the need for guide catheters with side holes and their inherent disadvantages.